The present invention relates to shoe constructions and the manufacture thereof, and in particular to buildups for shoes.
In order to increase the effective height of shoes whereby the level at which the foot is supported is higher than normal, it is known to construct an extension of the half sole and heel, which are generally adhesively secured to the existing sole of the shoe, and then attach a ground engaging second sole and a heel, which are made of leather or another suitable material such as nylon, to the bottom of the half sole and heel extensions. These extensions are commonly referred to in the trade as buildups. Shoes with buildups are often worn by persons having one leg shorter than the other, and the height of the buildup is equal to the differential in the lengths of the legs. Additionally, buildups can be employed on both shoes to make the wearer appear taller than he or she actually is.
Heretofore, difficulty has been encountered in the manufacture of shoes incorporating buildups in the case where a flexible foam material, such as crepe rubber, is used. Because of the flexible nature of the crepe rubber and because the shoe is flexed to a considerable degree when walking, the bonding and securing means, such as glue and nails, tend to pull out thereby requiring repair of the shoes. This tends to dislodge, not only the buildup from the sole of the existing shoe, but also the secondary soles and heels which are nailed to the bottom surfaces of the buildups. Moreover, the crepe material is quite heavy, and people wearing large buildups on one or both shoes will experience foot and leg fatigue after an extended period of walking or at the end of the day.